In cellular networks, one cell may cause interference to other cells. This may for example be due to an improper tilt angle of an antenna used to serve the cell with radio signals. Typically, a tilt angle which is too close to the vertical direction may result in overshooting of the radio signals to neighboring cells. For purposes of managing the cellular network, it is desirable to identify such overshooting, so that it can be resolved, e.g., by downtilting the antenna.
In “Impact of antenna downtilting on network performance in GERAN system”, by Wille et al., in IEEE Communication Letters, July 2005, vol. 9, no. 7, pp. 598-600 a cell overshooting indicator is described which is built from Timing Advance (TA) measurements available in base stations. Such a TA overshooting indicator is measured on a per-cell basis as the percentage of TA samples of users in a cell that fall beyond the nominal cell distance, defined as the average distance to neighbor sites. This indicator may be used to rank cells in the network in terms of the need for downtilting their antennas.
However, such TA measurements may in some cases fail to provide sufficient accuracy for identification of overshooting. Further, it may cause additional effort to obtain a required number of such TA measurements for statistical analysis. Moreover, such TA measurements do not reflect a level of interference caused by the cell, but rather constitute an estimate how far the radio signals reach from the cell. In some cases, radio signals may reach far into a neighboring cell, but still not constitute a relevant source of interference, e.g., because radio signals of the neighboring cell are significantly stronger at these locations.
Accordingly, there is a need for techniques which allow for efficiently managing a cellular network communication network in view of interference between cells.